1. Field of the Invention
The present invention relates generally to a bumper for a vehicle.
2. Description of Related Art
Motor vehicles typically use a bumper system at the front and rear end thereof. The bumper system typically includes a bumper beam that extends across the front and rear end of the vehicle. The respective bumper beams are typically attached to either a pair of rails or the vehicle frame. Many bumper systems include an energy absorption member that extends across and is secured to the bumper beam. In some cases, the bumper system includes a facia or cover located over the bumper beam.
The motor vehicle industry has established certain standards and must adhere to certain government regulations concerning low-speed vehicle impact. Further, vehicle bumpers are typically made of a low-weight, high-strength steel to maintain structural integrity and provide a bumper beam that can withstand impact at speeds of up to 5 mph without sustaining damage while at the same time maintaining a low weight to minimize overall vehicle weight. Accordingly, the bumpers typically have a high strength to weight ratio and are formed of a material that can be relatively easy to manufacture.
Prior art vehicle bumpers are typically manufactured using a roll forming process. Roll forming is a continuous metal forming process that takes sheet, strip or coiled stock and bends or forms it into a shape having an essentially identical cross-section by feeding the material between successive pairs of rollers that increasingly shape the material until the material reaches a desired cross-section. Accordingly, the respective roll forming tool limits the shape or cross-section of the workpiece such that it does not vary along its longitudinal axis. In some cases several roll formed parts are joined together to form a box-shaped member that forms the bumper. While roll forming is a particularly attractive manufacturing method for mass producing bumper beams using high-strength materials, roll forming limits the shape and configuration of the bumper. In addition using roll forming to make a complex bumper configuration or cross-section is often cost prohibitive.